I didn't have any great expectations for this day since clouds were passing over the sun intermitently.
The first setup was my LS 152 + Quark Chromosphere + Blackfly S 3.2Mp (1/1.8 inch sensor).
Then I setup my c9.25 with an Aries ERF in front and a 0.63X reducer + 3x telecentric + Quark Combo + Blackfly S 3.2 Mp camera.
I couldn't get much more than 1000 frames per video due to clouds but the seeing seemed to be moderately good.

I haven't had much luck with the single stack c9.25+Quark Combo with disk features but I can tell with the results below that this is going to be a killer combination for proms under good conditions.

Lou

The first 2 images are with the Lunt 152:

152a.jpg (742.87 KiB) Viewed 1119 times

152b.jpg (754.05 KiB) Viewed 1119 times

The real surprise happened with the c9.25 setup showing better detail than I remember in the past attempts (albeit with lesser
proms). The last 2 images are uncropped.

Thanks for your suggestion about using an Ha filter in the optical train. I see that both Baader and Astronomik have a 7nm Ha filter that's ok pricewise. I'm not entirely clear on why the filter should be ahead of all the optics at the back end of the scope. That puts it in a very high heat load region at "prime" focus(ERF does pass heat that is uncomfortable to the skin at the end of the scope). Placing the filter between the etalon and camera would expose it to a lower heat load but I want to
know if the ability of the filter to block undesirable wavelengths be affected on its location.

Thanks for your suggestion about using an Ha filter in the optical train. I see that both Baader and Astronomik have a 7nm Ha filter that's ok pricewise. I'm not entirely clear on why the filter should be ahead of all the optics at the back end of the scope. That puts it in a very high heat load region at "prime" focus(ERF does pass heat that is uncomfortable to the skin at the end of the scope). Placing the filter between the etalon and camera would expose it to a lower heat load but I want to
know if the ability of the filter to block undesirable wavelengths be affected on its location.

Lou

Lou, do not use a 7nm filter. It has IR leak. May be a 3nm has the same. Much better is to use a 35nm. It has no leakage in IR.

"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

The feedback on these Ha filters is a good example of why it's so great having people with technical or real world experience on this board that freely offer information. I currently use a 2" Baader UV/IR blocking filter on the nosepiece of telecentric for heat protection for the telecentric and the etalon but this doesn't provide any improvement in image contrast.

One question remaining, though, is whether the 35 nm filter offers any significant contrast boost in the image or whether I would have to use it in combination with another Ha filter to accomplish that. I understand why the 7nm filter, given its IR leakage, would not offer heat protection by itself. Would combining a 35nm with a 7nm provide more contrasty views since the 7nm is described as being able to cut undesirable wavelengths more sharply than the 35nm?

My own Quark completely refuses to work if a Baader 35nm filter is placed in front of it, irrespective of filter's distance and Quark tuning. It's not a matter of temperature because the tuning can't be recovered by heating/cooling the etalon chamber.

Much better is 7nm filter.

BTW, excellent images Lou, spicule details are fantastic.

Last edited by krakatoa1883 on Thu Oct 11, 2018 5:34 pm, edited 1 time in total.

Lou:
All beautiful images, but the ones taken with the 9.25" and the full Aries ERF are very very good.
I will try my 10" f/20 Mak with the Baader 35nm filter as son as I have good weather to see the Sun.
Regards,
Eric.

that is interesting about the 35nm filter and your quark, what is your complete setup arrangement?

I exposed the problem in this old discussion, however since then I couldn't find any reasonable explanation for such a behavior. In the meantime I sold the 35 and replaced with a front Baader ERF or a rear 7nm, depending on the telescope used.

Mark: are you using a secondary erf on your HaT telescope with your quark?

I found in the experiments I did it didn't make any difference. Best game changer I found was using the Edge HD 0.7 reducer ahead of the Quark instead of having the native f10 beam of the HaT feeding the Quark. After trying Airylab telecentric, Baader 4x telecentric, I found I get the best results with the native telecentric that comes with the Quark. I also found I get more transmission through by changing the 12.5mm filter on the nosepiece of the Quark with the 25mm version.

This discussion is getting very interesting now, especially with krakatoas previous post. it seems like everyone is having very different inconsistencies between usages here.

Quark behavior seems quite variable between different units. When I noted the problems with the 35nm filter my first thought was that the unit needed some "extra heat" that can't arrive to the etalon if an efficient IR blocker is put in front of the device. But in this case I should have been able to improve the image by rotating the tuning knob clockwise as this increases the etalon temperature, however doing so actually made things worse.

My second thought was the BF. Removing the internal telecentric and replacing it with an external amplifier while keeping the same f/ratio at the etalon distance and the 35nm filter on the diagonal nose, considerably improved images. In the latter configuration the Andover BF sees a much higher f/ratio (f/15 - f/20 instead of f/5 - f/7 depending on the telescope used) and is not directly behind the 35nm. Evidently this change "something" (but what ?) that allow the system to work properly.

Eventually, however, I was not satisfied with the filter and sold it.

@Mark, where did you purchase the 25 mm BF ? Can it be ordered to Andover directly from Europe ? Thanks

A couple of questions to pose here as the discussion evolves. First, in the spring of 2017 when I got the Airylab telecentric I met Frédéric at NEAF and he suggested adding a Ha filter in image train. Their telecentric has a 1.25" filter mount before the amplifier optics and can be tilted as well. I bought an Astronomic 12nm filter while at NEAF...link below

I have not had a lot of time to use this on the intended larger OTA (C9.25 Edge), but I really couldn't see much difference with or without the filter installed (tilted or not as well). This is in conjunction with a Daystar full aperture ERF (their Yellow glass version). My other option was the Baader UV/IR cut mounted ahead of the 4x Powermate or 3x Explore Scientific Tele-extender which seemed to be my best option. The filter used is a Daystar Quantum 0.45A PE filter. I'm curious to know what the thoughts are on this Ha as a secondary ERF.

The second questions refers to the comment made by Christian that Lou's image is off band...which side of center and by how much do you estimate the deviation? I'd also like to know what you base this on...I'd like to know to evaluate my own images in the future.

Maybe relevant maybe not but thought I'd put it here anyway.
Using a Baader D-ERF (Red glass) on my 152mm frac I find the exiting beam to be cool & not warm, Baader states that the D-ERF prevents thermal turbulence in the tube, prevents focus shift & stabilizes centre wavelength drift due to temperature changes.
With the Quark attached it appears to stay on band as required & the tuner acts as it should as & when I need it to.
Does ambient temp play a part, having had this setup pointed at the sun for as long as 7 hours straight in summer & the Quark performing as it should I would say no, I am sure other user's may had had issues though.